Re: DHCP option 60 and VLAN 10

Could you clarify what you mean by "set this interface as DHCP client", do you mean you are using the router configuration (GUI or CLI) to configure eth.10 to use DHCP? Since you are also manually creating a dhclient.conf and invoking dhclient, it's probably better to not use the GUI/CLI configuration and just do the manual steps.

Not sure if it's useful but here's what the client config looks like when it's configured through the configuration: